Charge forming apparatus



April 16, 1963 B. c. PHILLIPS 3,085,791

CHARGE FORMING APPARATUS Filed Aug. 23, 1960 3 Sheets-Sheet 1 INVENTORIBERNARD L. PHILLIPS.

ATTORNEY April 16, 1963 B. c. PHILLIPS CHARGE FORMING APPARATUS 2 M 0/ a6 MW 4 Q .m e e w p 5 4 2 M 2 4M m a I I 0 U 2 1% M 66 I 0 4 Z 2 .2 6 l1 ud w H. 0 3 L? 3 I (I r o /3 4 0 L m J a 7 5 22 8 2 7 fimwwm @w 0 g 2m 066 M n X \l 8 6 1 .m 0 a! nu 7 6 IN lE NTOR: BERNARD L. PHILLIPS.

BY M E ATTORNEY Aprll 16, 1963 B. c. PHILLIPS 3,085,791

CHARGE FORMING APPARATUS Filed Aug. 25, 1960 s sneets sneet s I4 1;: 3:.r vfi E5: 3 AV IIE-D- Emmy Li PHILLIPS.-

BY 0 g ATTORNEY United States Patent ce 3,085,791 CHARGE FORMINGAPPARATUS Bernard C. Phillips, Toledo, Ohio, assignor to The TillotsonManufacturing Company, Toledo, Ohio, a corporation of Ohio Filed Aug.23, 1960, Ser. No. 51,413 12 Claims. (Cl. 26135) This invention relatesto charge forming apparatus for delivering fuel and air mixtures to aninternal combustion engine and more especially to a charge formingapparatus or carburetor embodying a flexible diaphragm arranged to beinfluenced or actuated by aspiration in the mixing passage forautomatically regulating the delivery of fuel from a supply into themixing passage in accordance with the requirements of the engine.

Charge forming devices or carburetors of the diaphragm type have beenemployed with internal combustion engines and are particularlyadvantageous for use with engines adapted to be operated in extremeangular or inverted positions as the diaphragm is not appreciablyaffected by gravity and sensitive control of the fuel flow into thediaphragm chamber is obtained.

Diaphragm carburetors of this character have been employed in which thefuel conveying channels in the carburetor have been arranged at variousangles and in different planes and wherein the main orifice andsupplemental orifices have been arranged in different radial positionsin the mixing passage necessitating a carburetor body of substantialsize to accommodate the various components and fuel conveying channels.

The present invention embraces a charge forming apparatus or carburetorwherein the major fuel conveying channels are arranged in one planewhereby the size of the carburetor body is reduced.

Another object of the invention resides in the provision of a diaphragmcarburetor construction wherein the main fuel delivery system embodies acombined orifice and check valve unit pressed into a suitable apertureproviding a main fuel delivery orifice.

Another object of the invention resides in a carburetor constructionembodying a compact arrangement for controlling a fuel inlet valve underthe influence of a diaphragm, the inlet being provided with a screen orfilter to prevent foreign matter entering into the carburetor.

Another object of the invention resides in the provision of a carburetorof the diaphragm type wherein all the major metering channels and fuelconveying ducts are contained in a comparatively thin, generallycircular portion of the carburetor body whereby the lengths of the fuelconveying ducts are reduced to a minimum.

Another object of the invention embraces the provision of :a carburetorwherein the metering and fuel conveying channels are locatedsubstantially in a single plane whereby little hydrostatic change occursirrespective of whether the carburetor is operated in upright, tilted orinverted positions.

Another object of the invention resides in the provision of a carburetorof compact construction wherein extensive savings in material areeffected enabling the production of the carburetor at a greatly reducedcost.

Another object of the invention is the provision of a combined checkvalve and main fuel delivery means contained in a unit fitting which maybe readily inserted or removed from a bore in the carburetor and whereina portion of the unit provides a closure means for an end of the boreaccommodating the unit fitting and eliminating the use of a separateclosure.

A further object is the provision of a diaphragm type carburetor havinga body member fashioned to facilitate the positioning of the fuelmetering means in various 3,085,791 Patented Apr. 16, 1963 regions ofthe carburetor body whereby the carburetor may be accommodated tovarious installations with engines of different sizes.

A further object of the invention resides in positioning the main andsupplemental fuel delivery orifices in a common vertical planelengthwise of the mixing passage, the arrangement including a mainnozzle and valve unit constructed and arranged to provide a shallow fuelchamber disposed close to the mixing passage thereby reducing the liftrequired to eflect delivery of fuel into the mixing passage renderingthe carburetor more sensitive and reliable in operation.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se, and to economies of manufactureand numerous other features as will be apparent from a consideration ofthe specification and drawing of a form of the invention, which may bepreferred, in which:

FIGURE 1 is a top plan view of a charge forming device or carburetor ofthe invention;

FIGURE 2 is a longitudinal sectional view through the carburetor, theview being taken substantially on the line 2-2 of FIGURE 1;

FIGURE 3 is a side elevational view of the carburetor shown in FIGURE 1;

FIGURE 4 is an end elevational view of the carburetor illustrated inFIGURES 1 through 3;

FIGURE 5 is a transverse sectional view taken substantially on the line55 of FIGURE 1;

FIGURE 6 is a detail sectional view taken substantially on the line 6-6of FIGURE 1;

FIGURE 7 is a sectional view taken substantially on the line 7-7 ofFIGURE 3;

FIGURE 8 is .an enlarged detail sectional view illustrating a nozzle andvalve unit forming a component of the carburetor;

FIGURE 9 is a transverse sectional view taken substantially on the line9-9 of FIGURE 8;

FIGURE 10 is an isometric view of an element of the nozzle and valveunit;

FIGURE 11 is a top plan View showing a modifiedform of the carburetor;

FIGURE 12 is a longitudinal sectional view of the carburetor illustratedin FIGURE 11 showing a'modified form of venting means for the chamberbeneath the diaphragm;

FIGURE 13 is a sectional view similar to FIGURE 6 illustrating theadjustable fuel metering means positioned in a side region of thecarburetor, the view being taken substantially on the line 13-43 ofFIGURE 12;

FIGURE 14 is a detail sectional view taken substantially on the line1414 of FIGURE 11;

FIGURE 15 is a longitudinal sectional view similar to FIGURE 2illustrating a fuel pump associated therewith; FIGURE 16 is an enlargedtop plan view showing a modified form of nozzle and check valve unit;

FIGURE 17 is a sectional view taken substantially on the line 1717 ofFIGURE 16, and

FIGURE 18 is a sectional view illustrating another form of nozzle andcheck valve unit.

While the charge forming apparatus of the invention has particularutility for supplying combustible mixture to engines of the two cylindertype, it is to be understood that invention may be employed with fourcycle engines. The charge forming apparatus is particularly adaptablefor use with internal combustion engines for operating equipment such asmarine motors, mowers, air compressors, generators, ventilating fans,power hammers and portable engine operated equipment and is usablewherever the carburetor is subjected to extreme positions of tilt orinverted positions.

Referring to the drawings in detail and particularly to the arrangementshown in FIGURES 1 through 10, the charge forming apparatus orcarburetor is inclusive of a body or a body member which may be formedof cast metal or other suitable material of a nonporous character whichis resistant to deterioration by hydrocarbon fuels. The body member 10is formed with a mixing passage 12 which includes an air inlet region14, a Venturi 16 having a choke band or region of restriction 18 and amixture outlet region 26.

The portion of the body 10 adjacent the air inlet region is formed withbosses 22 bored to journally support a shaft 24 which is equipped with agenerally circular disctype valve 26 serving as a choke valve forstarting the engine. The choke valve shaft 24 is provided with amanipulating arm 27. The body 10 is provided with bosses 28 bored tojournally receive a shaft 30 which supports a generally circulardisc-type throttle valve 32 for regulating the fiow of fuel and airmixture to an engine with which the carburetor may be used.

An exterior portion of the throttle shaft 30 is provided with amanipulating arm 34, an adjustable abutment screw 36 being supported bythe body It) and engageable with the arm 34 for adjusting the engineidling position of the throttle valve 32. The carburetor body 10 isprovided with a mounting flange 38 having openings 40 to accommodatebolts (not shown) for securing the carburetor to the crarnkcase of a twocycle engine or to an intake manifold of an engine of a four cycle type.

A flange 42 adjacent the air inlet region 14 is formed with threadedopenings 44 to receive bolts or threaded members (not shown) forsecuring an air cleaner or air filter (not shown) to the carburetorbody. The body member 10 is fashioned with a shallow recess disposed inclose proximity to the mixing passage 12, the recess providing a fuelchamber 46 adapted to contain liquid fuel. Extending across the fuelchamber 46 and forming a flexible wall of the fuel chamber is a flexiblemember, diaphragm or membrane 48.

The diaphragm 48 is preferably of generally circular shape, and anannular gasket 50 is disposed between the peripheral region of thediaphragm 48 and a generally circular, disc-like portion 52 of the bodymember 10. The inner circular edge of the gasket 56 is preferably inregistry with the circular side wall defining the fuel chamber 46. Aclosure or cover plate 54 embraces the exterior major surface of thediaphragm 48.

The peripheral region of the closure plate 5'4 is provided with openingswhich are in registry with threaded bores in the portion 52 of the body10 to accommodate securing screws 56 which serve to secure the diaphragm48, gasket 50 and closure plate 54 in assembled relation with the bodymember 10. The central region of the cover or closure plate 54 isdepressed or recessed providing a clearance space or chamber 58 toaccommodate flexing movements of the diaphragm. The space or chamber 58is vented to the atmosphere through an opening 69 as shown in FIGURE 2.The closure member 54 may be formed of sheet metal or other suitablematerial.

The flexible diaphragm 43 is fashioned of a highly flexible,comparatively thin material which is imperforate or formed of a materialwhich is impregnated to render the same imperforate and which isresistant to deterioration by hydrocarbon fuels. The diaphragm 48 isreinforced by. a disc-like member 62 formed of sheet metal or moldedresin and is disposed contiguous with the major surface of the diaphragmadjacent the chamber 46. A second circular disc-like member 64 isdisposed at the opposite side of the diaphragm, the discs 62 and 64being held in assembled relation with the diaphragm by a rivet or member65.

The diaphragm 48, in the embodiment illustrated in FIGURES 1 through 7is arranged to regulate or control the flow of liquid fuel from a supplyinto the chamber 46. The carburetor body is formed with a boss 66provided with a threaded bore 67 accommodating the threaded portion of afitting 68 formed with a passage 69 to acommodate fuel flow. The fitting68 is provided with a nipple portion 70 which receives a flexible fuelsupply hose or tube (not shown).

The passage 69 in the fitting 68 is in communication with a chamber orpassage 72 formed in the carburetor body 10, a screen or filter 74 beingdisposed adjacent the end of the fitting 68 for preventing foreignparticles that may be contained in the fuel entering the carburetorbody. The body 10 is provided with a threaded bore adapted toaccommodate a fitting or valve cage 76 having a central passage in whichis slidably disposed a valve body 78 formed with a cone-shaped valveportion 80 at one end thereof.

An annularly shaped valve seat 82 -is disposed at the end of the fittingand is adapted for cooperation with the cone-shaped valve 80 to regulateor control fuel flow into the chamber 46. Pivotally supported orfulcrumed upon a pin 84 is a lever member 86, the pin 84 being providedwith a portion 87 threaded into a bore in the body 10 for securing thepin in position as shown in FIGURE 7. The long arm 88 of the lever 86 isadapted to be engaged by the head of the rivet 65 carried by thediaphragm 48, the short arm 90 of the lever 86 engaging the lower end ofthe valve body 78 as shown in FIG URE 5.

An expansive coil spring 92 is seated in a bore 93 formed in an upperwall of the fuel reservoir or chamber 46 as shown in FIGURE 5. Thespring 92 engages the long arm 88 of the lever 86 and biases the leverfor movement in a clockwise direction as viewed in FIG- URE 5, whichaction normally urges the valve 80 into seating position with theannular valve seat 82 to interrupt fuel flow into the fuel chamber 46.

The fuel chamber 46 is unvented and the diaphragm is flexed solely byaspiration or reduced pressure in the mixing passage 12 set up by airflow through the mixing passage. It is preferable to dispose the spring92 close to the fulcrum 84 of the lever 86, as a comparatively stiffspring may be employed and yet retain a high degree of sensitivity ofcontrol of the fuel control valve 80 by the diaphragm. A drain screw 96is provided for the fuel chamber 46 as shown in FIGURE 5 in the eventthat it is desired to drain the fuel from the chamber 46.

It should be noted that the fuel chamber 46 is made as shallow as ispracticable and as close to the mixing passage 12 as possible to effecta lifting of fuel from chamber 46 by low or reduced aspiration acting onthe diaphragm 48 and to reduce to a minimum the hydrostatic head ofliquid fuel on the diaphragm so that comparatively low velocity of airin the mixing passage initiates delivery of fuel through the nozzle 102.The upper wall of the chamber 46 is fashioned with a recess 98 of aconfiguration to accommodate pivotal movement of the lever 86 as shownin FIGURES 5 and 7.

The carburetor of the invention is inclusive of a main nozzle or orificeconstruction for high speed engine operation which is fabricated as aremovable unit 102 and a secondary fuel delivery system including engineidling and low speed orifices to facilitate idling of the engine and forlow speed engine operation. The fuel conveying channels and fuelregulating or metering means for the main orifice and secondary orificesystem are illustrated in FIGURES 6 and 7. The check valve and mainnozzle unit construction 102 is illustrated in FIGURES 8 and 9 and willbe hereinafter described in further detail.

The main nozzle unit construction 102 is pressed into a bore formed inthe body 10 whereby fuel for high speed engine operation is deliveredinto the mixing passage in the zone of the choke band or restrictedregion 18 of the Venturi construction 16. The supplemental or secondaryfuel delivery system is inclusive of a chamber 104, shown in FIGURES 2and 7, an engine idling orifice 106 and a low. speed orifice 108 incommunication with the chamber 104 being arranged to deliver fuel intothe mixing passage adjacent the region of the throttle valve 32.

The fuel conveying channels and fuel regulating or metering means areillustrated in FIGURES 6 and 7. As will be noted from FIGURE 7, the axesof the several fuel conveying channels or passages are arrangedsubstantially in a single plane and are contained in a circulardisc-like portion 52 of the carburetor body, providing for a compactarrangement and a smaller body construction than has heretofore beenpossible.

Angularly arranged in the disc-like portion 52 of the carburetor body isa passage or duct 110 in which is disposed a high speed fuel meteringvalve body 111 terminating in a needle valve portion 112, the needlevalve portion extending into and cooperating with a restricted passage114. The passage 114 is in communication with the recess 98 formed in awall of the fuel chamber 46 and facilitates fuel flow from the fuelchamber 46 to the main orifice construction and to the supplementary orsecondary fuel delivery orifices.

A passage 116 intersects the passage 110 and conveys fuel to the mainorifice construction 102 and to the engine idling and low speed orifices106 and 108. The valve body or member 111 has a threaded portion 115threaded into a bore in the body for regulating or adjusting theposition of a needle valve portion 112 and is provided with a knurledknob 117 for the purpose. A sealing gasket 118 is disposed in acounterbore for preventing leakage of fluid along the valve member, acoil spring 119 engaging the knurled knob 11 7 for exerting biasingpressure upon the seal 118 and establishing friction so as to maintainthe valve member 111 in adjusted position.

Arranged in parallelism with the passage 116 is a passage or duct 122,the passage 122 being in communication with the chamber 104 of thesecondary fuel delivery system through a restricted passage 124. Thepass-ages 116 and 122 are cored or molded into the carburetor body and,in the fuel passage arrangement illustrated in FIGURE 7, have theirouter ends closed by means of soft metal or lead plugs 126 and 127.

The passages 116 and 122 are connected by a passage or channel 130 and arestricted passage 132, as shown in FIGURE 7. The passage 130accommodates a valve member or body 134 formed with a needle valveportion 136 arranged for cooperation with the restricted passage 132 formetering or regulating fuel flow to the secondary orifices 106 and 108.The valve body 134 is provided with a threaded portion 138 threaded intoa bore in axial alignment with the passage 130 for adjusting theposition of the needle valve 136.

The valve body 134 is provided with a knurled knob 140 for manipulatingthe metering valve 136. A sealing gasket 142 is disposed in acounterbore formed in the.

shown in FIGURE 2 the end of the chamber 104 adjacent the fuel chamber46 is closed by means of a plug or cap 146.

From FIGURE 7 it will be seen that fuel flows from the fuel or diaphragmchamber 46 through the recess 98, restricted passage 114 past the needlevalve 112 to the main orifice construction 102, the latter deliveringfuel into the choke band region 18 of the Venturi 16. Fuel for the idleand low speed fuel delivery system flows through the same channels, andthruogh the passage 116, passage 130 past the needle valve 136 throughthe passage 132 and through the passages 122 and 124 into the chamber104, which supplies fuel to the engine idling orifice 106 and the lowspeed orifice 108 depending upon the position of the throttle 32 andhence the velocity of air flow through the mixture passage.

From FIGURE 7 is will be seen that the needle valve 112 meters orregulates the fuel delivered to both the main orifice construction 102and the secondary orifices 106 and 10:0, and the needle 136 meters orregulates fuel flow to the secondary orifices.

The carburetor of the invention is of a character which is operable invarious angular positions as Well as inverted positions, theseconditions being encountered where the carburetor is used with enginespowering chain saws which are adaptable for use in any position. Inorder to secure satisfactory operation in all positions of thecarburetor, a check valve means is provided in the main orificeconstruction to prevent back bleeding of air from the mixing passageinto the secondary orifice or fuel delivery system when the latter is inoperation.

As particularly shown in FIGURES 8 and 9, the main or primary nozzlearrangement and valve construction are constructed as a unit 102 whichmay be readily inserted and removed from a bore in the carburetor bodywhich opens into the mixing passage and into the fuel reservoir orchamber 46. The nozzle unit 102 is inclusive of a cylindrically-shapedfitting or cage formed of metal such as brass or other suitablematerial. The fitting is provided with an axial bore 152 which does notextend entirely through the fitting. Arranged axially with the bore 152is a counterbore 154 of slightly larger diameter which accommodates avalve means such as a ball check valve 156.

The passage 152 is of a diameter such that at thejuncture of the passagewith the counterbore 154 provides an annular seat 158 for the ball valve156. The counterbore 154 opens into the choke band region 18 of theVentu-ri 16 and functions as the main or primary fuel delivery nozzlefor high speed engine operation. The fuel delivery end region of thefitting 150 is formed with a second counterbore accommodating anannularly shaped member 160 formed of thin sheet metal or the like whichis integrally formed with a diametrically arranged bar or abutment 162shown in FIGURES 8 and 10.

In assembly, the check ball 156 is disposed in the counterbore 154, theannularly shaped member 160 positioned in the second counterbore and theend region of the fitting 150 swaged over the periphery of the mem-' ber160, as shown at 164- in FIGURE 8, to retain the member 160 in the endregion of the fitting.

The abutment provided by the diametrically extending bar or grid 162 isnormally spaced above the ball valve 156 a sufficient distance tofacilitate movement of the valve away from the seat 158 to provide forfuel flow through passage 152 around the valve 156 and into the mixingpassage.

The fitting 150 is provided with a circumferential or peripheral recess166, as shown in FIGURE 8 and with passage, the check valve 156 isseated to block the flow of air from the mixing passage through the mainnozzle and thus prevent air bleeding into the fuel conveyed to thesecondary orifices.

The check valve 156 is preferably fashioned of lightweight material suchas nylon (polyamid resin) or polyoxymethylene resin (Delrin) renderingit operable under the influence of a minimum lift to elevate the ballfrom its seat 158. The relation between the diameter of the When one orboth of the secondary orifices 106 and 108 are delivering fuel into themixing counterbore 154 and the diameter of the ball check 156 is suchthat the annular region between the periphery of the ball and thecounterbore provides a cross-sectional area sufiicient to admit passageof the maximum fuel flow required for high speed engine operation.

It should be noted that the circular edge region 172 of the recess 166is rounded or chamfered as shown in FIGURE 8. In assembling the nozzleand check valve unit 102 in the bore formed in the carburetor body, thefitting with the check ball and check ball retainer 160 in preassembledrelation is pressed into the bore through the end of the bore openinginto the fuel chamber 46. If it is desired to remove and replace thecheck valve and nozzle assembly 102, the fitting 156 may be drivenentirely through the bore in the body to extrude the fitting into theVenturi.

The fitting may thus be replaced by another fitting assembly of the samecharacter. By rounding or chamfering the region 172 defining thecircular recess 168, the fitting may be driven through the bore in thebody and replaced with another fitting without damage to the boresurface. Heretofore it has been a practice of providing a separatethreaded plug or closure for the bore accommodating a threaded nozzlefitting at the region of opening of the bore into the fuel chamber.

In the construction illustrated in FIGURE 8, the lower portion 174 ofthe fitting is imperforate and forms, as a part of the fitting, aclosure for the end of the bore adjacent the fuel chamber 46. Byproviding the diametrically arranged passages 168 between the peripheralrecess 166 and the central bore 152, the fitting 150 may be assembled inthe bore in the body with assurance that fuel may flow through the mainnozzle or through the circumferential recess and passages 168 to thesecondary fuel delivery system irrespective of the radial position ofthe passages 168.

From the foregoing it will be apparent that there is provided a mainnozzle and check valve unit construction which may be quickly and easilyassembled in a carburetor body and which provides a closure of the endof the bore into which the fitting is assembled. FIG- URES 1 through 7illustrating the carburetor are slightly enlarged for purposes ofillustration as the carburetor for use with engines of low horsepower issmaller than the scale shown in the drawings.

The operation of the charge forming apparatus or carburetor of theinvention is as follows: As the fuel chamber 46 is unvented, thediaphragm is flexed or moved under the influence of aspiration orreduced pressure set up in the mixing passage by air flow therethrough.Reduced pressure effective in the chamber 46 flexes the diaphragmupwardly, as viewed in FIGURES 2 and 5, cansing the lever 86 to be swungin a counterclockwise direction, as viewed in FIGURE 5, whereby thevalve 80 moves away from its annular seat 82, facilitating flow ofliquid fuel through the inlet fitting '68 past the valve 80, thepolygonally shaped valve body 78 and into the chamber 46.

Fuel from the chamber flows through the recess 98, the restrictedpassage 114 past the high speed metering needle valve 112, through thecircular recess 166' and passages 168 into the central bore 152, pastthe check valve 156 and is discharged into the Venturi of the mixingpassage 12 for high speed engine operation. The amount of fuel flowingpast the inlet valve 80 is regulated by the relative position of thediaphragm and is only sufi'icient to satisfy the requirements of theengine.

When the throttle is moved toward closed position, air velocity throughthe mixing passage decreases, and the pressure increases in the fuelchamber 46, and in conjunction with the pressure of the spring 92, thevalve 80 is moved toward closed position as the diaphragm 48 movesdownwardly, as viewed in FIGURES 2 and 5.

Fuel for the idling and low speed orifices flows through the peripheralrecess 166 in the fitting 150 or through passages 168, through passages116 and 130, past the metering needle 136, through the restriction 132,passages 122 and 124 into the chamber 104. If the throttle valve 32 isin engine idling position, fuel is delivered through the orifice 106. Ifthe throttle valve 32 is partially opened, fuel may be delivered throughboth orifices 106 and 108. When the throttle is opened a greaterdistance, the main orifice 154 comes into operation and the secondaryorifices gradually decrease fuel delivery into the mixing passage.

FIGURES 11 through 14 illustrate certain modifications of theconstruction shown in FIGURES 1 through 7. In the arrangement shown inFIGURES 11 through 14, the body 10' is of the same construction as thebody 10 hereinbefore described. The fuel inlet control arrangement ofthe construction shown in FIGURES 11 through 14 is identical with thefuel inlet valve mechanism shown in FIGURES 1 through 6. The diaphragm48 influences the position of a lever 86 for controlling the fuel inletvalve mechanism.

The carburetor in this form of the invention is inclusive of a chokevalve 26', a throttle valve 32' and a Venturi 16. The carburetorincludes the main fuel delivery nozzle and check ball unit 102 and thesecondary engine idling and low speed orifices 1G6 and 108 which are inthe same relative positions as illustrated in FIG- URE 2. As illustratedin FIGURE 12, a modified form of closure plate 180 is provided forsecuring the diaphragm 48' and the gasket 50 to the carburetor body 10'.

In this form of the invention the chamber 182, between the lower orobverse face of the diaphragm and the cover plate 180, is vented to theair inlet region 14' of the mixing passage. As shown in FIGURE 12 anangularly arranged air inlet or vent tube 184 is disposed in a boreformed in the wall of the air inlet region 14'. The tube 184 is incommunication with the space or chamber 182 by means of registeringpassageways 185 and 186 formed respectively in the body 10 and closure180 whereby the space 182 is vented through the air inlet region 14 ofthe mixing passage.

In the usual arrangement, an air cleaner is secured to the carburetorbody at the air inlet region and hence the space 182 is thus vented toair adjacent the air cleaner and the liability of dust or foreign matterentering the space 182 is substantially eliminated. Furthermore thisform of venting maintains pressure :balance of the carburetor againstthe restriction of the air cleaner if partial clogging should occur.

In the form of the invention illustrated in FIGURES 11 through 14, theadjustable fuel metering controls for the high speed or main orifice andthe secondary fuel delivery system are disposed in a side region of thecarburetor body. This arrangement is illustrated in FIG- URES 11 and 13.

As particularly shown in FIGURE 13, the passage 116' has a threadedportion to accommodate a threaded valve body similar in construction tothe valve 115 shown in FIGURE 7, the valve body having a knurledmanipulating knob 117'. The passage 122 is formed with a threaded regionto accommodate the threaded portion of a valve body 134' which is oflesser length than the metering valve 134 shown in FIGURE 7 butfunctions in the same manner as valve member 134, viz. to meter orregulate fuel flow to the chamber 104 for delivery through the secondaryorifices 106' and 103. The valve body 134 is provided with a knurledmanipulating knob 140'.

As shown in FIGURE 14, a passage 188 connects the fuel chamber 46' withthe duct or passage 116' whereby fuel flows to the main orifice and ballvalve unit 102 for delivery into the Venturi of the mixing passage, orfuel may flow through passage 116, angularly arranged passage restrictedpassage 132, past the needle valve portion 136' of the valve body 134,thence through the restriction 124' into the chamber 104 for deliverythrough the secondary orifices.

The operation of the modified form of the invention illustrated inFIGURES 11 through 14 is substantially the same as the operation of theform of the invention shown in FIGURES 1 through 7 as hereinbeforeexplained. The passage 110 shown in FIGURE 13 which is cored or cast inthe carburetor body :11} is not drilled for communication with any otherpassage or duct and performs no function in this form of carburetor. Thepassage 130 which establishes communication between passages 116' and122 has its outer end region closed by means of a soft metal plug H2.

It will be apparent from the foregoing description that the carburetorbody of the type shown in FIGURE 7 and in FIGURE 13 may be cast ormolded and the passages 110, 116, 130' and 122' may be fashioned in partin molding the carburetor body and certain of these passagessubsequently machined or processed to provide the fuel conveying andmetering arrangement shown in FIGURE 7, or machined to provide the fuelconveying and metering arrangement illustrated in FIGURE 13.

In the arrangement shown in FIGURE 7, the high speed adjusting valvemember 115 and the metering valve member 134- are disposed in theconvergently arranged passages 110 and :134) and are arranged to bemanipulated from the air entrance end of the carburetor, while in thearrangement shown in FIGURE 13 the metering valve members 115' and 134'are arranged in parallel relation and are accessible from a side of thecarburetor body. Other arrangements of fuel ducts or passages than thoseillustrated in FIGURES 7 and 13 may be employed. For example, in FIGURE13, separate fuel supply ports for passage-s 116' and :122 directly tochamber 46' may be used and passage 130' eliminated.

FIGURE 15 illustrates a diaphragm type pump construction associated withthe carburetor for feeding fuel to the inlet valve region of thecarburetor body. In the arrangement shown in FIGURE 15, the cover member54, shown in FIGURE 2, is replaced with a disclike member 200 formedwith a space 2612 to accommodate flexing movements of the diaphragm 48and is vented by a vent passage 203. The disc-like member 200 forms onesection of a pump construction 2134, the disc 200 being formed with arecess 2% providing a pumping chamber.

Secured to the member 262 by means of Screws 2433 IS a second pump bodysection 210 which is formed w th a recess providing a fuel chamber 212adapted to receive fuel from a supply to be pumped into the carburetor.Disposed between the pump body sections 2% and 210 is a pumpingdiaphragm 214. The pumping chamber 206 is connected with a source ofvarying fluid pressure such as the crankcase of a two cycle engine foreffecting vibration of the pumping diaphragm 2 14 setting up a pumpingaction in the fuel chamber 212. The pump construction illustrated inFIGURE 15 may be of the character illustrated in my Patent 2,796,838,granted June 25, 1957.

The pump body section 210 is provided with a chamber 216 which receivesfuel through a strainer or screen 218 from a supply through an inletfitting 220 formed on a closure member 222 secured to the lower portionof the pump section 2111 by means of a screw 224.

The pump body section 214 is provided with fuel conveying ducts orpassages (not shown) which communicate with ports controlled by flapvalves (not shown) provided as integral parts of the pumping diaphragm214 to establish fuel flow through the fuel chamber 212 to the region ofthe inlet valve in the carburetor.

Thus it will be apparent that the forms of carburetor of the inventionillustrated may be supplied with fuel from a tank or fuel receptacle bygravity, or the fuel may 11) be pumped into the carburetor chamber 46through an arrangement of the character illustrated in FIGURE 15.

FIGURES 16 and 17 illustrate a modified form of main or primary nozzleand check valve construction 102 adapted to be pressed into a bore inthe carburetor body for delivering fuel into the Venturi of the mixingpassage. The unit 102' includes a cylindrically shaped fitting or cage230 formed of brass or other suitable material. The fitting 230 isformed with an axial bore 232 which does not extend entirely through thefitting. The upper region of the fitting is provided with a counterbore234 which accommodates a circular disc-shaped valve member 236 of lesserdiameter than that of the counterbore 234.

The region of transition between the upper terminus of the axial bore232 and the counterbore 234. is shaped to provide an annular ledge 238forming a seat for the disc valve 236. The upper end region of thefitting is formed with a second counterbore which receives a valveretainer member or abutment 240 generally of the shape of a Maltesecross. In assembling the components, the disc valve 236 is inserted inthe counterbore 234, the retainer disposed in the second counterbore inthe fitting, and the upper edge of the fitting swaged or deformed as at242 over the ends of the arms of the retainer 240 to secure the retainerto the fitting.

The check valve 236 is arranged for unimpeded movement in the spaceprovided by the counterbore 234 be tween the valve seat 238 and theretainer 240 to facilitate fuel flow through the bore or passage 232around the periphery of the valve member 236 past the arms of theretainer 246 and into the mixing passage of the carburetor. The fitting230 is provided with a peripheral recess 166 and aligned transverselyextending bores forming passages 16% to facilitate fuel flow as hereinbefore described in connection with the nozzle and check valve unit 102.

The valve member 236 is preferably made of comparatively lightweightmaterial. The valve member 236 may be made of polyoxymethylene (Delrin),phenolformaldehyde resin (Bakelite), polyester resin (Mylar), polytriflnorochloroethylene (KelF) polyamid resin (nylon) or other suitablematerial.

FIGURE 18 illustrates another form of combined nozzle and check valvearrangement for delivering fuel into the mixing passage for high speedengine operation. A portion of the carburetor body 10 is illustrated inFIG- URE 18 and is provided with a bore 250 between the fuel chamber 46of a carburetor and the restricted region 18 of the Venturi 16. A casingor housing 252 having a smooth exterior circular cylindricalconfiguration or shape is of a diameter whereby the same may be pressedor forced into the bore 250. The casing 252 is provided with a bore 254and with a counterbore 256, the

juncture of the bore and counterbore forming an annular valve seat 258.The spherical or ball-shaped valve 260 is contained within thecounterbore 256 and is adapted to engage the annular seat 258. Anabutment member of the same type shown at 160 in FIG- URE 10, isdisposed in the fuel outlet end region of the casing 252 to preventdislodgement of the valve member 2619. -A disc valve member of thecharacter illustrated at 236 in FIGURE 17 may be used in lieu of theball type valve member.

The entrance of the bore 250 adjacent the fuel chamber in the carburetoris formed with a counterbore 262 to accommodate a disc-type closuremember or plate 264 which may be in the form of a Welsh plug. The spacebetween the closure plate 264 and the end of the casing 252 within thebore is in communication with the passage 116 formed in the body 10 ofthe carburetor and is adapted to convey fuel into the space provided bythe bore 250 through the bore 254 past the ball valve 260 for deliveryinto the Venturi of the mixing passage.

It is desirable that the diaphragm fuel chamber be answer disposed closeto the mixing passage so that low air velocity in the mixing passageestablishes sufficient aspiration or reduced pressure to actuate thediaphragm and effect delivery of fuel into the mixing passage.

It is apparent that, within the scope of the invention, modificationsand different arrangements may be made other than as herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehending all variations thereof.

Iclaim:

1. In combination, charge forming apparatus including a body formed witha mixing passage, an unvented fuel chamber formed in the body, aflexible diaphragm forming a wall of the fuel chamber, a fuel inlet forthe fuel chamber, a valve member for the fuel inlet, means including alever establishing operative connection between the valve member and thediaphragm for controlling the position of the valve member forregulating fuel flow from a supply into the fuel chamber, said bodybeing formed with a bore opening into the mixing passage, a fittinghaving a smooth cylindrical exterior surface pressed into said bore, anend region of the fitting extending into the mixing passage, saidfitting having a fuel passage formed therein opening into the mixingpassage, a secondary fuel delivery orifice formed in said body openinginto the mixing passage, duct means formed in the body for conveyingfuel from the fuel chamber to the secondary orifice, and means in saidfitting to prevent air bleeding through the passage in the fitting intothe duct means when the secondary orifice is delivering fuel into themixing passage.

2. In combination, charge forming apparatus including a body formed witha mixing passage, an unventcd fuel chamber formed in the body, aflexible diaphragm forming a wall of the fuel chamber, a fuel inlet forthe fuel chamber, a valve member for the fuel inlet, means including alever establishing operative connection between the valve member and thediaphragm for controlling the position of the valve member forregulating fuel flow from a supply into the fuel chamber, said bodybeing formed with a smooth surfaced bore between the fuel chamber andthe mixing passage, a fitting having a smooth cylindrical exteriorsurface pressed into said bore, said fitting having a fuel passageformed therein opening into the mixing passage, 21 secondary fueldelivery orifice in said body opening into the mixing passage, ductmeans formed in the body for conveying fuel from the fuel chamber to thesecondary orifice, a ball valve in said fitting to prevent air bleedingthrough the passage in the fitting into the duct means when thesecondary orifice is delivering fuel into the mixing passage, and meansclosing the end of the bore adjacent the unvented fuel chamber.

3. An apparatus of the character disclosed, in combination, a carburetorbody formed with a mixing passage, a fuel chamber in said body, aflexible diaphragm forming a wall of the fuel chamber, means controlledby said diaphragm for admitting liquid fuel from a supply into saidchamber, a bore in said body between the chamber and the mixing passage,primary means for delivering liquid fuel from the chamber int-o themixing passage including a combined fuel delivery nozzle and check valveunit in said bore comprising a casing having a smooth circularcylindrical surface, a fuel conveying passage formed axially in saidcasing, a counterbore of greater cross-sectional area than said passageformed in said casing, a ball valve member disposed in said counterboreand adapted to obstruct air flow from the mixing passage into thepassage in said casing, abutment means arranged to maintain the ballvalve member in the counterbore, a peripheral recess formed in theexterior cylindrical wall of the casing, a transverse bore in the casingin communication with the passage in said cas-. ing, means formedintegrally on said casing for closing the end of the bore adjacent thefuel chamber, and sec- 12 ondary orifice means for delivering liquidfuel into the mixing passage at low engine speeds.

4. An apparatus of the character disclosed, in combination, a carburetorbody formed with a mixing passage, a fuel chamber in said body, aflexible diaphragm forming a wall of the chamber, means controlled bythe diaphragm for admitting liquid fuel into said chamber from a supply,a bore of uniform diameter in said body between the chamber and mixingpassage, a combined fuel delivery nozzle and check valve unit in saidbore comprising a fitting having a smooth circular cylindrical exteriorsurface, an end of said fitting extending through the bore into themixing passage, a fuel conveying duct formed axially in said fitting, acounterbore formed in said fitting, valve member disposed in saidcounter-bore and adapted to obstruct air flow from the mixing passageinto the duct in the fitting, a recess formed in the exteriorcylindrical surface of the fitting, a transverse bore in the casing incommunication with the recess and the duct for conveying fuel to theduct for delivery from the fitting into the mixing passage, means forclosing the end of the bore accommodating the fitting, and a secondaryorifice in said body opening into the mixing passage arranged to deliverliquid fuel into the mixing passage at low engine speeds.

5. In combination, charge forming apparatus including a body formed withan air and fuel mixing passage, a fuel chamber formed in the body, aflexible diaphragm forming a wall of the fuel chamber, a fuel inlet forthe fuel chamber, a valve member for the fuel inlet, means establishingoperative connection between the valve memher and the diaphragm forcontrolling the position of the valve member for regulating fuel flowfrom a supply into the fuel chamber, said body being formed with a boreopening into the mixing passage, a fitting having a smooth cylindricalexterior surface pressed into said bore, said fitting having an endportion extending into the mixing passage and having a fuel passageformed therein opening into the mixing passage, a secondary fueldelivery orifice in said body opening into the mixing passage, ductmeans formed in the body for conveying fuel from the fuel chamber to therecess in the fitting and the secondary orifice, said fitting having aperipheral recess formed therein, a channel in said fitting between therecess and the passage in the fitting, and check valve means in saidfitting arranged to close the passage in the fitting to prevent airbleeding through the passage in the fitting into the duct means when thesecondary orifice is delivering fuel into the mixing passage.

6. In combination, charge forming apparatus including a body formed withan air and fuel mixing passage, a comparatively shallow unvented fuelchamber formed in the body, a flexible diaphragm forming a wall of thefuel chamber, a fuel inlet for the fuel chamber, a valve memher for thefuel inlet, means establishing operative connection between the inletvalve member and the diaphragm for controlling the position of the valvemember for regulating fuel flow from a supply into the fuel chamher,said diaphragm being actuated by aspiration in the mixing passage, saidbody being formed with a bore opening into the mixing passage, a nozzlemember formed with a smooth cylindrical exterior surface pressed intothe here, said nozzle member having a fuel passage formed thereinopening into the mixing passage and forming a main fuel dischargeorifice, a secondary fuel delivery orifice in said body opening into themixing passage, duct means formed in said body arranged to convey liquidfuel from the fuel chamber to the main and secondary fuel deliveryorifices, manually adjustable means for metering fuel flow to thepassage in the nozzle member, and an element in said nozzle memberarranged to prevent air bleeding through said main orifice into the ductmeans when the secondary orifice is delivering fuel into the mixingpassage.

7. In combination, charge forming apparatus including 13 a body formedwith a mixing passage, an unvented fuel chamber formed in the body, aflexible diaphragm forming a wall of the fuel chamber, a fuel inlet forthe fuel chamber, a valve member for the fuel inlet, said diaphragmbeing arranged to control the position of the inlet valve member forregulating fuel flow from a supply into the fuel chamber, said bodybeing formed with a bore opening into the mixing passage, a fittingformed with a smooth cylindrical exterior surface pressed into saidbore, a portion of the fitting projecting into the mixing passage, saidfitting having a fuel passage formed therein opening into the mixingpassage, a secondary fuel delivery orifice in said body opening into themixing passage, duct means formed in the body for conveying fuel fromthe fuel chamber to the secondary orifice, and a disc valve in saidfitting to prevent air bleeding through the passage in the fitting intothe duct means when the secondary orifice is delivering fuel into themixing passage.

8. in combination, charge forming apparatus including a body formed withan air and fuel mixing passage, an unvented fuel chamber formed in thebody, a flexible diaphragm forming a wall of the fuel chamber, a fuelinlet for the fuel chamber, a valve member for said fuel inlet, saiddiaphragm being arranged to control the relative position of the valvemember for regulating fuel flow from a supply into the fuel chamber,said body being formed With a bore opening into the mixing passage, afitting formed with a smooth cylindrical exterior surface pressed intosaid bore, said fitting having a fuel passage formed therein openinginto the mixing passage providing a main orifice for delivering fuelinto the mixing passage, said fitting having a channel in communicationwith the passage and the bore in the body, a second fuel deliveryorifice in said body opening into the mixing passage, duct means formedin said body arranged to convey fuel from the fuel chamber to thechannel in the fitting and the second fuel delivery orifice, meansassociated with the duct means for metering fuel flow through the ductmeans, check valve means in said fitting to prevent air bleeding throughthe main orifice into the duct means when said second orifice isdelivering fuel into the mixing passage, said fitting being formed witha portion closing the region of the bore opening into the fuel chamber.

9. In combination, charge forming apparatus including a body formed withan air and fuel mixing passage, an unvented fuel chamber formed in thebody, a flexible diaphragm forming a wall of the fuel chamber, a fuelinlet for the fuel chamber, a valve member for said fuel inlet, meansincluding a lever arranged to be actuated by movement of the diaphragmfor controlling the valve member for regulating fuel flow from a supplyinto the fuel chamber, said body being formed with a bore opening intothe mixing passage, a fitting having a smooth cylindrical exteriorsurface pressed into said bore, said fitting having a fuel passageformed therein opening into the mixing passage providing a main orificefor delivering fuel into the mixing passage, said fitting having achannel in communication with the passage and the bore in the body, asecond fuel delivery orifice in said body opening into the mixingpassage, duct means formed in said body arranged to convey fuel from thefuel chamber to the passage in the fitting and the second fuel deliveryorifice, means associated with the duct means for metering fuel flowthrough the duct means, a ball check valve in said fitting to preventair bleeding through the main orifice into the duct means when saidsecond orifice is delivering fuel into the mixing passage, said fittingbeing formed with a portion closing the region of the bore opening intothe fuel chamber.

10. In combination, charge forming apparatus including a body formedwith an air and fuel mixing passage, a comparatively shallow unventedfuel chamber formed in the body, a flexible diaphragm forming a wall ofthe fuel chamber, a fuel inlet for the fuel chamber, a valve member forthe fuel inlet, means including a lever establishing operativeconnection between the inlet valve member and the diaphragm forcontrolling the position of the valve member for regulating fuel flowfrom a supply into the fuel chamber, said diaphragm being actuated byaspiration in the mixing passage, said body being formed with a smoothsurfaced bore opening into the mixing passage, a nozzle member having asmooth cylindrical surface pressed into the bore, said nozzle memberhaving a fuel passage formed therein opening into the mixing passage andforming a main fuel discharge orifice, a secondary fuel delivery orificein said body opening into the mixing passage, closure means for theregion of the smooth surfaced bore opening into the fuel chamber, ductmeans formed in said body arranged to convey liquid fuel from the fuelchamber to the main and secondary fuel delivery orifices, a counterboreformed in said nozzle member, check valve means movably disposed in saidcounterbore arranged to prevent air bleeding through said main orificeinto the duct means when the secondary orifice is delivering fuel intothe mixing passage, and an abutment carried by the nozzle member forretaining the valve means in said counterbore.

11. In combination, charge forming apparatus including a body formedwith an air and fuel mixing passage, a comparatively shallow unventedfuel chamber formed in the body, a flexible diaphragm forming a wall ofthe fuel chamber, a :fuel inlet for the fuel chamber, a valve member forthe fuel inlet, said diaphragm being arranged to control the relativeposition of the valve member for regulating fuel flow from a supply intothe fuel chamber, said diaphragm being actuated by aspiration in themixing passage, said body being formed with a smooth surfaced boreopening into the mixing passage, a nozzle member having a smoothcylindrical surface pressed into the bore, said nozzle member having afuel passage formed therein opening into the mixing passage and forminga main fuel discharge orifice, a secondary fuel delivery orifice in saidbody opening into the mixing passage, closure means for the region ofthe smooth surfaced bore opening into the fuel chamber, duct meansformed in said body arranged to convey liquid fuel from the fuel chamberto the main and secondary fuel delivery orifices, a counterbore formedin said nozzle member, an element disposed in said counterbore arrangedto prevent air bleeding through said main orifice into the duct meanswhen the secondary orifice is delivering fuel into the mixing passage,and an abutment carried by the nozzle member for retaining the discvalve in said counterbore.

12. In combination, charge forming apparatus including a body formedwith an air and fuel mixing passage, a comparatively shallow unventedfuel chamber formed in the body, a flexible diaphragm forming a wall ofthe fuel chamber, a fuel inlet for the fuel chamber, a valve member forthe fuel inlet, said diaphragm being arranged to control the relativeposition of the valve member for regulating fuel flow from a supply intothe fuel chamber, said diaphragm being actuated by aspiration in themixing passage, said body being formed with a smooth surfaced boreopening into the mixing passage, a nozzle member having a smoothcylindrical surface pressed into the bore, said nozzle member having afuel passage formed therein opening into the mixing passage and forminga main fuel discharge orifice, a secondary fuel delivery orifice in saidbody opening into the mixing passage, closure means for the region ofthe smooth surfaced bore opening into the fuel chamber, duct meansformed in said body arranged to convey liquid fuel from the fuel chamberto the main and secondary fuel delivery orifices, a first adjustablemeans for metering fuel flow from the fuel chamber to the main fueldischarge orifice, a second adjustable means for metering fuel flow tosaid second fuel delivery orifice, a counterbore formed in said nozzlemember, check valve means movably dis- References Cited in the file ofthis patent UNITED STATES PATENTS Phillips Feb. 7, 1956 Brown Feb. 18,1958

1. IN COMBINATION, CHARGE FORMING APPARATUS INCLUDING A BODY FORMED WITH A MIXING PASSAGE, AN UNVENTED FUEL CHAMBER FORMED IN THE BODY, A FLEXIBLE DIAPHRAGM FORMING A WALL OF THE FUEL CHAMBER, A FUEL INLET FOR THE FUEL CHAMBER, A VALVE MEMBER FOR THE FUEL INLET, MEANS INCLUDING A LEVER ESTABLISHING OPERATIVE CONNECTION BETWEEN THE VALVE MEMBER AND THE DIAPHRAGM FOR CONTROLLING THE POSITION OF THE VALVE MEMBER FOR REGULATING FUEL FLOW FROM A SUPPLY INTO THE FUEL CHAMBER, SAID BODY BEING FORMED WITH A BORE OPENING INTO THE MIXING PASSAGE, A FITTING HAVING A SMOOTH CYLINDRICAL EXTERIOR SURFACE PRESSED INTO SAID BORE, AN END REGION OF THE FITTING EXTENDING INTO THE MIXING PASSAGE, SAID FITTING HAVING A FUEL PASSAGE FORMED THEREIN OPENING INTO THE MIXING PASSAGE, A SECONDARY FUEL DELIVERY ORIFICE FORMED IN SAID BODY OPENING INTO THE MIXING PASSAGE, DUCT MEANS FORMED IN THE BODY FOR CONVEYING FUEL FROM THE FUEL CHAMBER TO THE SECONDARY ORIFICE, AND MEANS IN SAID FITTING TO PREVENT AIR BLEEDING THROUGH THE PASSAGE IN THE FITTING INTO THE DUCT MEANS WHEN THE SECONDARY ORIFICE IS DELIVERING FUEL INTO THE MIXING PASSAGE. 